Metal-Free C-C Cross Coupling: Electrosynthesis of Azaheterocycles through Anodic Oxidation Cyclization of 1,6-Enynes

A straightforward synthesis of azaheterocycles has been developed through electrochemically aerobic oxidation cyclization using a user-friendly undivided electrolytic cell at room temperature under catalyst-free conditions. This green and practical electrosynthesis strategy features good functional group, diverse electronic and steric properties tolerance. On the basis of a series of mechanistic investigations, including isotope labeling, singlet oxygen inhibiting, superoxide radical anion inhibiting, radical-trapping, cyclic voltammetry and controlled potential electrolysis experiments, a possible N-centered radical-initiated mechanism was proposed.